Reciprocating piston compressor having improved noise attenuation

Abstract

A reciprocating piston compressor having a suction muffler and a pair of discharge mufflers to attenuate noise created by the primary pumping frequency in the primary pumping pulse. The suction muffler is disposed along a suction tube extending between the motor cap and the cylinder head of the compressor. The discharge mufflers are positioned in series within the compressor to receive discharge gases from the compression mechanism and are spaced one quarter of a wavelength from each other so as to sequentially diminish the problematic or noisy frequencies created during compressor operation. The motor/compressor assembly including the motor and compression mechanism is mounted to the interior surface of the compressor housing by spring mounts. These mounted are secured to the housing to define the position of the nodes and anti-nodes of the frequency created in the housing to reduce noise produced by natural frequencies during compressor operation.

1. A compressor assembly comprising:
 a compression mechanism having an inlet into which a gas substantially at suction pressure is received, and an outlet from which gas compressed by said compression mechanism is discharged substantially at a discharge pressure; 
 a motor comprising a rotor and a stator, said stator substantially surrounding said rotor and having an end, said rotor operatively coupled with said compression mechanism; 
 an end cap disposed over said stator end, said end cap having an interior in which is gas substantially at suction pressure; and 
 a suction tube of variable length through which said compression mechanism inlet and said end cap interior are in fluid communication, said suction tube comprising first and second tubes which are in sliding, telescoping engagement, whereby the length of said suction tube may be adjusted through relative axial movement of said first and second tubes. 
 
   
   
     2. The compressor assembly of  claim 1 , further comprising a sealing member disposed between said first and second tubes. 
   
   
     3. The compressor assembly of  claim 1 , wherein said suction tube is provided with a muffler through which gas substantially at suction pressure flows from said end cap interior to said compression mechanism inlet. 
   
   
     4. The compressor assembly of  claim 3 , wherein said muffler is fixed relative to one of said first and second tubes. 
   
   
     5. The compressor assembly of  claim 4 , wherein said muffler is fixed relative to said compression mechanism inlet. 
   
   
     6. The compressor assembly of  claim 3 , wherein said muffler has an expansion chamber into which one of said first and second tubes opens. 
   
   
     7. The compressor assembly of  claim 1 , further comprising a housing in which said compression mechanism and said motor are disposed, said housing having an interior which is substantially at suction pressure and in fluid communication with said end cap interior.